2 * Copyright 2007 Bobby Bingham
3 * Copyright 2012 Robert Nagy <ronag89 gmail com>
4 * Copyright 2012 Anton Khirnov <anton khirnov net>
6 * This file is part of FFmpeg.
8 * FFmpeg is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Lesser General Public
10 * License as published by the Free Software Foundation; either
11 * version 2.1 of the License, or (at your option) any later version.
13 * FFmpeg is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * Lesser General Public License for more details.
18 * You should have received a copy of the GNU Lesser General Public
19 * License along with FFmpeg; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
25 * a filter enforcing given constant framerate
28 #include "libavutil/common.h"
29 #include "libavutil/fifo.h"
30 #include "libavutil/mathematics.h"
31 #include "libavutil/opt.h"
32 #include "libavutil/parseutils.h"
38 typedef struct FPSContext {
41 AVFifoBuffer *fifo; ///< store frames until we get two successive timestamps
43 /* timestamps in input timebase */
44 int64_t first_pts; ///< pts of the first frame that arrived on this filter
45 int64_t pts; ///< pts of the first frame currently in the fifo
47 AVRational framerate; ///< target framerate
48 char *fps; ///< a string describing target framerate
51 int frames_in; ///< number of frames on input
52 int frames_out; ///< number of frames on output
53 int dup; ///< number of frames duplicated
54 int drop; ///< number of framed dropped
57 #define OFFSET(x) offsetof(FPSContext, x)
58 #define V AV_OPT_FLAG_VIDEO_PARAM
59 #define F AV_OPT_FLAG_FILTERING_PARAM
60 static const AVOption fps_options[] = {
61 { "fps", "A string describing desired output framerate", OFFSET(fps), AV_OPT_TYPE_STRING, { .str = "25" }, .flags = V|F },
65 AVFILTER_DEFINE_CLASS(fps);
67 static av_cold int init(AVFilterContext *ctx, const char *args)
69 FPSContext *s = ctx->priv;
72 s->class = &fps_class;
73 av_opt_set_defaults(s);
75 if ((ret = av_set_options_string(s, args, "=", ":")) < 0) {
76 av_log(ctx, AV_LOG_ERROR, "Error parsing the options string %s.\n",
81 if ((ret = av_parse_video_rate(&s->framerate, s->fps)) < 0) {
82 av_log(ctx, AV_LOG_ERROR, "Error parsing framerate %s.\n", s->fps);
87 if (!(s->fifo = av_fifo_alloc(2*sizeof(AVFilterBufferRef*))))
88 return AVERROR(ENOMEM);
90 av_log(ctx, AV_LOG_VERBOSE, "fps=%d/%d\n", s->framerate.num, s->framerate.den);
94 static void flush_fifo(AVFifoBuffer *fifo)
96 while (av_fifo_size(fifo)) {
97 AVFilterBufferRef *tmp;
98 av_fifo_generic_read(fifo, &tmp, sizeof(tmp), NULL);
99 avfilter_unref_buffer(tmp);
103 static av_cold void uninit(AVFilterContext *ctx)
105 FPSContext *s = ctx->priv;
108 av_fifo_free(s->fifo);
111 av_log(ctx, AV_LOG_VERBOSE, "%d frames in, %d frames out; %d frames dropped, "
112 "%d frames duplicated.\n", s->frames_in, s->frames_out, s->drop, s->dup);
115 static int config_props(AVFilterLink* link)
117 FPSContext *s = link->src->priv;
119 link->time_base = av_inv_q(s->framerate);
120 link->frame_rate= s->framerate;
121 link->w = link->src->inputs[0]->w;
122 link->h = link->src->inputs[0]->h;
123 s->pts = AV_NOPTS_VALUE;
128 static int request_frame(AVFilterLink *outlink)
130 AVFilterContext *ctx = outlink->src;
131 FPSContext *s = ctx->priv;
132 int frames_out = s->frames_out;
135 while (ret >= 0 && s->frames_out == frames_out)
136 ret = ff_request_frame(ctx->inputs[0]);
139 if (ret == AVERROR_EOF && av_fifo_size(s->fifo)) {
141 for (i = 0; av_fifo_size(s->fifo); i++) {
142 AVFilterBufferRef *buf;
144 av_fifo_generic_read(s->fifo, &buf, sizeof(buf), NULL);
145 buf->pts = av_rescale_q(s->first_pts, ctx->inputs[0]->time_base,
146 outlink->time_base) + s->frames_out;
148 if ((ret = ff_start_frame(outlink, buf)) < 0 ||
149 (ret = ff_draw_slice(outlink, 0, outlink->h, 1)) < 0 ||
150 (ret = ff_end_frame(outlink)) < 0)
161 static int write_to_fifo(AVFifoBuffer *fifo, AVFilterBufferRef *buf)
165 if (!av_fifo_space(fifo) &&
166 (ret = av_fifo_realloc2(fifo, 2*av_fifo_size(fifo)))) {
167 avfilter_unref_bufferp(&buf);
171 av_fifo_generic_write(fifo, &buf, sizeof(buf), NULL);
175 static int end_frame(AVFilterLink *inlink)
177 AVFilterContext *ctx = inlink->dst;
178 FPSContext *s = ctx->priv;
179 AVFilterLink *outlink = ctx->outputs[0];
180 AVFilterBufferRef *buf = inlink->cur_buf;
184 inlink->cur_buf = NULL;
186 /* discard frames until we get the first timestamp */
187 if (s->pts == AV_NOPTS_VALUE) {
188 if (buf->pts != AV_NOPTS_VALUE) {
189 ret = write_to_fifo(s->fifo, buf);
193 s->first_pts = s->pts = buf->pts;
195 av_log(ctx, AV_LOG_WARNING, "Discarding initial frame(s) with no "
197 avfilter_unref_buffer(buf);
203 /* now wait for the next timestamp */
204 if (buf->pts == AV_NOPTS_VALUE) {
205 return write_to_fifo(s->fifo, buf);
208 /* number of output frames */
209 delta = av_rescale_q(buf->pts - s->pts, inlink->time_base,
213 /* drop the frame and everything buffered except the first */
214 AVFilterBufferRef *tmp;
215 int drop = av_fifo_size(s->fifo)/sizeof(AVFilterBufferRef*);
217 av_log(ctx, AV_LOG_DEBUG, "Dropping %d frame(s).\n", drop);
220 av_fifo_generic_read(s->fifo, &tmp, sizeof(tmp), NULL);
222 ret = write_to_fifo(s->fifo, tmp);
224 avfilter_unref_buffer(buf);
228 /* can output >= 1 frames */
229 for (i = 0; i < delta; i++) {
230 AVFilterBufferRef *buf_out;
231 av_fifo_generic_read(s->fifo, &buf_out, sizeof(buf_out), NULL);
233 /* duplicate the frame if needed */
234 if (!av_fifo_size(s->fifo) && i < delta - 1) {
235 AVFilterBufferRef *dup = avfilter_ref_buffer(buf_out, ~0);
237 av_log(ctx, AV_LOG_DEBUG, "Duplicating frame.\n");
239 ret = write_to_fifo(s->fifo, dup);
241 ret = AVERROR(ENOMEM);
244 avfilter_unref_bufferp(&buf_out);
245 avfilter_unref_bufferp(&buf);
252 buf_out->pts = av_rescale_q(s->first_pts, inlink->time_base,
253 outlink->time_base) + s->frames_out;
255 if ((ret = ff_start_frame(outlink, buf_out)) < 0 ||
256 (ret = ff_draw_slice(outlink, 0, outlink->h, 1)) < 0 ||
257 (ret = ff_end_frame(outlink)) < 0) {
258 avfilter_unref_bufferp(&buf);
266 ret = write_to_fifo(s->fifo, buf);
267 s->pts = s->first_pts + av_rescale_q(s->frames_out, outlink->time_base, inlink->time_base);
272 static int null_start_frame(AVFilterLink *link, AVFilterBufferRef *buf)
277 static int null_draw_slice(AVFilterLink *link, int y, int h, int slice_dir)
282 AVFilter avfilter_vf_fps = {
284 .description = NULL_IF_CONFIG_SMALL("Force constant framerate"),
289 .priv_size = sizeof(FPSContext),
291 .inputs = (const AVFilterPad[]) {{ .name = "default",
292 .type = AVMEDIA_TYPE_VIDEO,
293 .min_perms = AV_PERM_READ | AV_PERM_PRESERVE,
294 .start_frame = null_start_frame,
295 .draw_slice = null_draw_slice,
296 .end_frame = end_frame, },
298 .outputs = (const AVFilterPad[]) {{ .name = "default",
299 .type = AVMEDIA_TYPE_VIDEO,
300 .rej_perms = AV_PERM_WRITE,
301 .request_frame = request_frame,
302 .config_props = config_props},
304 .priv_class = &fps_class,